As technology evolves into era of sub-micron, there is a desire to integrate different circuit elements into a single chip or integrated circuit (IC). There is also a desire to integrate different chips both vertically and horizontally in a single package to form a 2.5D or 3D IC package. Nevertheless, it is difficult to integrate these different types of devices in a single chip or a single package. Particularly, some of these devices may have different power requirements. Sometimes, additional voltage regulators or charge pumps, etc. may be employed to cater for different circuits which require different power supplies. Hence, additional circuit and long power supply line are generally used to provide power supply to the whole chip or package. These undesirably consume a lot of power and chip or package space and are not effective in providing power to the different devices.
From the foregoing discussion, it is desirable to provide a device with high circuit performance which requires less power consumption and/or with reduced chip or package size. It is also desirable to provide a smaller product which enhances portability. In addition, it is desirable to provide a process for forming a device which is fully compatible with the process for forming 2.5D and 3D IC or package in the future.